Piston ring structure



March 14, 1944. T. E. MCFALL ETAL PISTON RING STRUCTURE- Original Filed oct. 26, 1938 III (2' mflowfiflfclil BY Old/67 (id 072 072, M

INVENTOR.

Patented Mar. 14, 1944 UNITED STATES, PATENT OFFICE 2,343,919, I

' rrs'ros nmc' s'rauc'runn Origina- 1 application October 26, 1938, Serial No.

236,976. Divided and this application January 2, 1943, Serial No. 471,128

4 Claims. (Cl. 309-45) small in area, thereby assuring a high unit wall pressure for a relatively moderate ring tension; thus promoting emcient oil scraping action without unduly increasing friction losses and cylinder wear. The ring which has been provided is particularly useful and practical.

This is a division .of our application, Serial Number 236,976, filed by us on October 26, 1938.

An understanding of the invention may be had from the following description taken in connection with the accompanying drawing, in which:

Figure 1 is a transverse section through a piston at the innermost piston groove, the piston ring being shown in plan, with one of the narrow ring members removed.

Fig. 2 is a fragmentary elevation of the piston and ring of our invention.

Fig. 3 is a fragmentary section taken longitudinally of the piston and transversely of the ring, on the plane H of Fig. 1.

Fig. 4 is a perspective view of a fragmentary part of the spreading and spacing member of the ring.

Like reference characters refer to like parts in the different figures of the drawing.

The piston I is of conventional construction in which, adjacent to its end farthest away from the crank shaft a plurality of ring receiving grooves are cut around the piston in one or more of which grooves the ring of our invention is to be placed. The groove has passages 3 through the walls of the piston connecting the bottom of the ring groove with the interior of the piston, which is hollow.

The piston ring of our invention includes two thin lateralring elements, which are adapted to 'engage the cylinder wall and which are usually cular outline when compressed within the cylinder bore and are generally between twenty and forty thousandths of an inch in thickness, though it is to be understood that the design of the ring element 4 is not necessarily restricted to the specific construction or dimensions herein disclosed, but that either or both of them may optionally be composed of multiple juxtaposed circular segments or of any other suitable construction designed'to more effectively limit the quantity of lubricating oil conveyed along the cylinder walls into the combustion chamber. When installed in a ring groove such as the groove 2, one of these ring members 4 lies against the upper side of the groove and the other at the lower side, whereby between the adjacent sides of the ring element 4 there is a considerable annular space.

The ring is completed by a spring ribbon member, which serves as a spreader (or-expander) and spacer element. This element has inner bowed portions I1 which adjacent their ends bear against the bottom of the groove 2, the

material then being narrowed and curved into return bends 19, one at each end of the inwardly bowed section ll, thence continued back in two straight sections 20 which approach each other and are then U-bent at 2 I joining integrally with the outer connection section at 22. This provides a spacing and. spreader member, which may also be termed a combined expander and spacer element, for the ring members 4, which are held apart by the elongated loops or outwardly bowed spacer reaches, which are of less axial width than the expander reaches l'l, portions of the material being removed at both the upper and lower edge portions of the spacer reaches. Shoulders I8 are provided where the material of the spacer and spreader member is reduced in width as shown in Fig. 4, the height of the shoulders being substantially equal to the thickness of the ring elements 4. the central portions of the outwardly bowed expander sections or reaches H which are joined at each side by the inwardly bowed connecting reaches to the spacer reaches, the connecting reaches being adapted to engage the bottom' of the piston groove in which the assembly is installed. The spacer reaches extend outwardly between the adjacent sides of the ring elements, spacing them apart and holding them in their positions in the ring groove.

The portions "and 22 may have openings In of suitable shape and cross sectional area pierced, slotted or notched for the passage of oil to the ring groove from whence it may pass inwardly The ring members 4 bear against 2 through the openings at I to the interior of the piston. One at the portions 22 may be modiiied' to provide a parting in the spring ribbon element as indicated at H or the ends oi the spring strip may optionally be riveted, clipped, welded, brazed or otherwise suitably united to iorm a substantially continuous band it sodesired;

The intermediate or expander spacer member oi the ring assembly is made from thin ilat ribbon steel stock preferably and may be oi a thickness and tom so as to provide the necessary pressure oi the outer ring members 4 at their outer edges against the cylinder wall. The

ring which bear against the cylinder wall, and

has ample passage ior the oil which is collected.

by the ring and carried to the bottom oi the ring Iroove.

While there has been shown the ring members l as thin flat ring members, it is to be understood that by the-term ring member not only will a single member such as shown in Fig. 4

be comprehended, but that a composite strucgroove in a piston and having spaced outwardly bowed sections, the end portions 01' which are adapted to bear against the bottom oi the ring groove, and then continued in reverse bends and in sections extending toward and approaching 'each other, each of said sections being reversely bent and integrally connecting with an outer section, thereby iorming an elongated loop between each oi the two consecutive bowed secconstruction is not expensive to make, is readily assembled and installed in the ring groove, pro-- vides the necessary tension ior the parts I oi the.

tions, the ends of said loop overlapping the ad- Jacent portions oi the bowed sections and shaped to lie between the inner and outer edges oi the ring members, said loop having its edge portions eaph cut away a distance equal substantially to the thickness oi a ring member, as and for the purpose specified.

a,s4s,a1e

2. A composite piston ring assembly comprising I a pair oi thin split expansible cylinder wall engaging elements oi wear resisting material. a com-' bined expander and space: element iormed oi ribbon steel and having a plurality oi spaced outwardly bowed expander reaches 'engageable with the inner edges oi said cylinder wail engaging elements and having a plurality oi outwardly bowed spacer reaches alternating with said first named reaches and of substantially greater radial height, said spacer reaches being oi axial width equal to the spacing oi said cylinder wall engaging elements to engage between said cylinder wall engaging elements and constitute spacers thereior, said spacer reaches being Joined at each side thereoi tosaid expander reaches by inwardly bowed reaches constituting thrust reaches for engagement with the bottom oi a piston ring groove in which the assembly is installed.

3. A composite piston ring assembly comprising a pair oi .axially spaced cylinder w'all engaging elements, and a combined spacer and expander spring member comprising a plurality oi spaced outwardly bowed expander reaches engageable with the inner edges oi said cylinder wall engagf ing elements, and a plurality oi outwardly bowed spacer reaches alternating with said expander reaches and Joined thereto at each side by inwardly bowed connecting reaches engageable with the bottom oi a piston ring groove in which the assembly is installed, said spacer reaches extending outwardly between saidcylinder wall engaging elements and being oi axial width equal to the axial spacing of the cylinder wall engaging elements, so as to engage and constitute spacer elements ior said cylinder wall engaging elements.

4. A combined spacer and expander spring element for a piston ring assembly, comprising a split spring member having a plurality oi spaced outwardly bowed expander reaches, a plurality oi spacer reaches outwardly bowed to a greater radial extent and being of lesser axial dimension than said expander reaches, said spacer reaches alternating with said expander reaches being Joined thereto at each side by inwardly boyed connecting reaches of substantial length engageable with the bottom oi a piston groove i which the assembly is installed.

THURLOW E. MOFALL. OLIVER G. NORTON. 

